End low-skilled immigration. Work permits are the way to secure Brexit Britain's borders

Today, Theresa May will warn global leaders assembled at the United Nations of the dangers of “uncontrolled mass migration”. It is hardly in doubt that such migration from the EU was one of the key drivers of the vote to leave the EU in June.

Fortunately, Brexit – if correctly negotiated – means that Britain will have the opportunity to manage its borders better than ever before. First of all we need to set out who from the EU we welcome.

I strongly favour continued free movement for tourists, business visitors, students, genuine marriage partners and retired people. This would minimise social and economic disruption with our European neighbours and would enable us to remain an active and engaged partner in Europe after we have left the Union.

Some 35 million EU nationals arrive in the UK every year. Of course, only those who intend to stay more than a year are counted as migrants. But the first key fact is that roughly 70 per cent of these EU migrants come here to work. This, therefore, is where we have to look to get the numbers down and reduce the strain on our public services and infrastructure.

The second key fact is that about 80 per cent of these EU workers are in low-skilled work, so a system of work permits confined to skilled workers would reduce the numbers substantially. It would not be the Australian system (which is designed to increase Australia’s population). We have our own system which could be suitably adapted, as the Prime Minister has pointed out.

The number of such work permits would have to be capped, and we would need to assume that the EU would reciprocate with work permits in some form. But the truth is that though our present cap on non-EU workers has been heavily criticised by employers, in its five years of existence it has never, on an annual basis, been reached. So a well-judged cap on EU migration would reassure the public that the numbers were being brought under control without undue difficulties for industry.

One category that should not be restricted is the transfer of senior staff within international companies. That already applies to non-EU staff, such as the Japanese, and must also be applied to EU personnel. By contrast, tight conditions would be needed over the self-employed as this could become a loophole wide open to exploitation. There will inevitably be winners and losers as a result of these measures.

Some employers, for example in the agricultural and hospitality sectors, will face problems of transition. They are bound to complain vociferously but it is not as if their employees, mainly from Eastern Europe, are going to disappear in a puff of smoke. There will be a period of years in which their numbers will tend to run down and during which employers could make some adjustments. They could invest in productivity improvements or improve their pay and conditions so as to draw into the labour force some of the 1.5 million British workers who are currently unemployed.

There will be other losers – those, for example, who have benefited from cheaper nannies and cheaper restaurants. The winners will be those whose jobs, wages and local services have been under pressure and who, accordingly, voted in large numbers for Brexit.

In all the arguments that will arise it will be important to remain crystal clear about the objective. The public have voted for control of EU migration. Control must mean a substantial reduction in numbers or the public will rightly feel that they have been deceived. Our calculation is that, in the medium term, an immigration regime of the kind I have outlined would reduce net migration from the EU by about 100,000 a year from its present level of 180,000. That would be a major contribution towards the Government’s overall objective of bringing immigration down to a reasonable and acceptable level. It would also be a win for us all.